I'm getting "found character that cannot start any token while scanning for the next token"

Hi there,
I have been running Ruby on Rails on my laptop for about a month now, but when I wanted to run the server in this instance (and it was working fine a few hours ago) I now receive this message. How can I get the server to run again please?

C:\Sites\LaunchPage>rails s
C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/psych.rb:203:in `parse': (<unknown>):
found character that cannot start any token while scanning for the next token at line 17 column 17 (Psych::SyntaxError)
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/psych.rb:203:in `parse_stream'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/psych.rb:151:in `parse'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/psych.rb:127:in `load'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/figaro-0.6.3/lib/figaro.rb:21:in `raw'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/figaro-0.6.3/lib/figaro.rb:17:in `env'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/figaro-0.6.3/lib/figaro/railtie.rb:7:in `block in <class:Railtie>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/lazy_load_hooks.rb:34:in `call'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/lazy_load_hooks.rb:34:in `execute_hook'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/lazy_load_hooks.rb:42:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/application.rb:67:in `inherited'
from C:/Sites/LaunchPage/config/application.rb:13:in `<module:LaunchPage>'
from C:/Sites/LaunchPage/config/application.rb:12:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:53:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:53:in `block in <top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:50:in `tap'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'